A characteristic optical variability time scale in astrophysical accretion disks

Burke, Colin J.; Shen, Yue; Blaes, Omer; Gammie, Charles F.; Horne, Keith; Jiang, Yan-Fei; Liu, Xin; McHardy, Ian M.; Morgan, Christopher W.; Scaringi, Simone; Yang, Qian

Abstract

Accretion disks around supermassive black holes in active galactic nuclei produce continuum radiation at ultraviolet and optical wavelengths. Physical processes in the accretion flow lead to stochastic variability of this emission on a wide range of time scales. We measured the optical continuum variability observed in 67 active galactic nuclei and the characteristic time scale at which the variability power spectrum flattens. We found a correlation between this time scale and the black hole mass extending over the entire mass range of supermassive black holes. This time scale is consistent with the expected thermal time scale at the ultraviolet-emitting radius in standard accretion disk theory. Accreting white dwarfs lie close to this correlation, suggesting a common process for all accretion disks.

Citation

Burke, C. J., Shen, Y., Blaes, O., Gammie, C. F., Horne, K., Jiang, Y.-F., Liu, X., McHardy, I. M., Morgan, C. W., Scaringi, S., & Yang, Q. (2021). A characteristic optical variability time scale in astrophysical accretion disks. Science, 373(6556), 789-792. https://doi.org/10.1126/science.abg9933

• Journal Article Type: Article
• Online Publication Date: Aug 13, 2021
• Publication Date: Aug 13, 2021
• Deposit Date: Oct 26, 2021
• Publicly Available Date: Oct 26, 2021
• Journal: Science
• Print ISSN: 0036-8075
• Electronic ISSN: 1095-9203
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 373
• Issue: 6556
• Pages: 789-792
• DOI: https://doi.org/10.1126/science.abg9933
• Public URL: https://durham-repository.worktribe.com/output/1233120
• Related Public URLs: https://arxiv.org/abs/2108.05389